Too Much of a Good Thing: Popular Vitamins That Can Hurt You

If you tuned into The Daily Show recently, you would have heard Jon Stewart’s guest, David Agus, a physician and author of the new best-selling book The End of Illness, fret about what could be called America’s vitamin abuse problem.

There have been 50 large-scale studies on supplements, he said, and not one has shown a benefit in heart disease or cancer. “I don’t get it,” he said. “Why are we taking these?”

Agus is not alone in his frustration. Other experts liken buying vitamins to flushing money down the toilet. In some cases, they mean it literally: If the body gets more of certain vitamins than it needs, it often excretes the excess in urine.

That doesn’t stop Americans from spending about $28 billion a year on dietary supplements, including vitamins and herbal supplements.

In some cases, people may be spending money only to put their health at risk. “As Americans, we think more is better, but that’s not the case with vitamins,” says Dee Sandquist, a registered dietician and spokesperson for the Academy of Nutrition and Dietetics. Here are three popular vitamin supplements that prove you can, in fact, get too much of a good thing.

Get the nutritional lowdown from our anti-agin cheat sheet.

Vitamin E

Supplement skeptics often point to the story of vitamin E, which was once considered a promising tool for cancer prevention. The National Cancer Institute was so hopeful that vitamin E supplements would decrease rates of prostate cancer that in 2001 it funded a study designed to test the theory. Instead, the findings revealed that the men who took vitamin E were 17 percent more likely—not less—to develop the disease.

While vitamin E is a key player in immune function and cell communication, it’s best obtained through diet—in foods like wheat germ, sunflower seeds, and broccoli—and worst when taken regularly in high doses. Like many vitamins, it appears to lose its main benefits when taken in excess.

Read about the top 5 diabetes-healing supplements.

NEXT: Vitamin A >>